Merge "Remove __INTRODUCED_IN_NO_GUARD_FOR_NDK(21)." am: 833ad6ee51

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2631630

Change-Id: Iba731871b587a6d60c17413e548a7be6c29c4d48
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>